Here are some tips we've come across. Feel free to add your own:

• Keep your tires properly inflated. Tires should be inflated to the pressure recommended for your vehicle; usually you can find this number inside the door frame or in your owner’s manual. For every three pounds below recommended pressure, fuel economy goes down by about 1 percent. Tires can lose a pound of pressure a month, so check pressure regularly, and especially before going on a long trip or carrying heavy loads. Also: Don’t buy “aggressive” tread tires if you don’t need them.

• Buy low-rolling-resistance replacement tires. Switching to a typical set of replacement tires lowers a vehicle’s fuel economy by as much as 4 percent, says greenercars.org. LRR tires are specially designed to improve a vehicle’s fuel economy, the site says, adding that most major tire manufacturers now produce LRR models.
• Check your fuel economy every few weeks. If it’s going down, you might have a problem with your engine or brakes.

• Get a tune-up. Says greenercars.org: Whether you do it yourself or go to a mechanic, a tune-up can increase your fuel economy. Follow owner’s manual guidelines. Be sure to check for worn spark plugs, dragging brakes and low transmission fluid; have your wheels aligned and tires rotated; and replace the air filter if needed. Make sure all used vehicle fluids are recycled or disposed of safely.

• Change the oil. In addition to making your car or truck last longer, replacing the oil and oil filter regularly will also help fuel economy. Ask the service station if they recycle used oil, or take your old oil to someplace that does recycle. Use API certified “energy conserving” motor oil, or ask for recycled oil as a replacement.